Sgt Todd said: "When we got there he was hiding behind a telephone pole firing at people as they ran around.

"He fired at me and I fired back. I was about 15 yards away. I could see into his eyes and he was calm. We did what we had to do, I wish we could have got there sooner."

Sgt Munley, who is only 5ft tall, is being treated for her wounds in hospital and has been described by friends as a "ball of fire" and a "great cop." When she arrived she saw Hasan firing at a fleeing, wounded soldier. She chased him and opened fire only for Hasan to turn and unleash his "cop killer" weapon.

Sgt Munley is married to Matthew Munley, a member of the special forces who has done two tours of Iraq.

Her stepmother, Wanda Barbour, said: "She is a very great person with a great spirit. We are just so grateful and thankful to the Lord that she's safe." The eruption of violence was over in just 10 minutes.

It began as 300 soldiers had been waiting to get vaccinations and have their eyes tested at a Soldier Readiness Center. Some witnesses reported that Hasan shouted "Allahu Akbar!" during the chaos.

Specialist Elliot Valdez, who survived, said: "I felt like I was back in Iraq. The noise, the chaos. It felt like Iraq."

The victims included a pregnant woman. Francheska Velez, 21, from Chicago, was filling out paperwork when the shooting started.

She had only just returned from a tour three days before and was expecting a baby boy in May.

Hasan's family said in a statement that his alleged actions were "despicable and deplorable." His cousin Nader Hasan said: "Our family is filled with grief. Our family loves America. We are proud of our country." In the days before the attack Hasan had been saying goodbye to friends, had given away his possessions and begun distributing copies of the Koran to neighbours.

At 2.37am and 5am on the day of the massacre he called Willie Bell, a neighbour at his apartment block, and left a message saying: "Nice knowing you, old friend. I'm going to miss you."

Mr Nelson was later interviewed for four hours by the FBI after it emerged Hasan had borrowed his computer for two months, even though he had his own.

Police are also looking for a man in Islamic dress who was seen going into Hasan's apartment two days before the massacre.

Alice Thompson, 53, who manages the two-storey block of flats, told the Telegraph: "It was very unusual because he had never had anyone round before. He had long black hair and a moustache and a dark complexion.

"He stayed about five minutes and then left. We'd never seen him before."

The following day Hasan knocked on the door of his next door neighbour Patricia Villa, 47 and gave her many of his belongings, including clothes, furniture and vegetables, and a copy of the Koran.

"He said he was going to Oklahoma on Thursday morning and then deploying to Afghanistan," she told the Telegraph.

"He came in and put the bags down in the living room and he seemed nice and normal. I didn't think it was odd because sometimes people don't want to throw things away. I'm just shocked."

On the morning of the massacre Hasan was seen throwing garbage bags into a rubbish skip at the back of the building.

Mrs Thomson said: "It was the first time I'd seen him throw anything away. I saw there was shredded paper in there. After it happened the police came and took the bags away."

She said Hasan paid $325 a month rent and had paid six months in advance. Despite telling her he was leaving for Afghanistan, he didn't ask for any money back.